Content distribution is becoming more and more demanding as multimedia data and contents can reach anywhere and anytime. Users are happy with the convenience and flexibility, and they can enjoy entertainment easily and efficiently. On the other hand, content owners are worried about the illegal usage of their property. There is a balance between two sides.
There are a lot of protection techniques for protecting the content, such as data encryption, watermarking, etc. They have been implemented in many content distribution applications. It seems different system employs different kinds of mechanisms and protection techniques to distribute content with protection. All the terminals or content consuming devices in that case are only able to play and consume the content that is provided by the same content provider. They cannot exchange their terminal or device to playback different contents.
In MPEG-4 context, a standardisation group has been working on MPEG-4 IPMP Extension. The solution is able to achieve both of the following:                1. Allow the same protected content to be consumed on different vendors' MPEG-4 IPMP Terminals. This will be fully enabled.        2. Allow the same content to be protected by different vendors' IPMP Tools. This will be assisted to as large extent as possible.        
In MPEG-2 context, there is a CA (Conditional Access) system that defines a minimum set of common CA elements necessary to achieve interoperability between different CA systems. However, there is no real inter-operability here, as not enough components are defined, and the architecture offered by CA is not flexible enough.
It is very difficult to produce the same terminal to play different MPEG-2 contents provided by different content providers in such case. In other words the same protected MPEG-2 content cannot be played back in different CA system.
On the other hand, CA system defines a common scrambling algorithm, this makes hardware implementation simple, however, this makes the whole architecture too rigid. IPMP tool should not be fixed to certain tool beforehand, it should allow more flexibility for vendors to choose their favourite tool in their IPMP system. In such case it is necessary to define some standard way and interface to provide both better flexibility and security at the same time.
Hence, a flexible and interoperable IPMP system is needed in MPEG-2 system for content protection.
To define a flexible and interoperable IPMP system structure for MPEG-2 to allow:                1. The same protected MPEG-2 content to be consumed on different vendors' MPEG-2 IPMP Terminals. This will be fully enabled.        2. The same MPEG-2 content to be protected by different vendors' IPMP Tools. This will be assisted to as large extent as possible.        
To provide the standard way for IPMP system implementers to build the whole IPMP system for MPEG-2 from encoder, channel distribution, to terminal in a secure manner;